DUHAMEL DU MONCEAU, HENRI LOUIS (1700-1782), French botanist and engineer, son of Alexandre Duhamel, lord of Denainvilliers, was born at Paris in 1700. Having been requested by the Academy of Sciences to investigate a disease which was destroying the saffron plant in Gâtinais, he discovered the cause in a parasitical fungus which attached itself to the roots, and this achievement gained him admission to the Academy in 1728. From then until his death he busied himself chiefly with making experiments in vegetable physiology. Having learned from Sir Hans Sloane that madder possesses the property of giving colour to the bones, he fed animals successively on food mixed and unmixed with madder; and he found that their bones in general exhibited concentric strata of red and white, whilst the softer parts showed in the meantime signs of having been progressively extended. From a number of experiments he was led to believe himself able to explain the growth of bones, and to demonstrate a parallel between the manner of their growth and that of trees. Along with the naturalist Buffon, he made numerous experiments on the growth and strength of wood, and experimented also on the growth of the mistletoe, on layer planting, on smut in corn, &c. He was probably the first, in 1736, to distinguish clearly between the alkalis, potash and soda. From the year 1740 he made meteorological observations, and kept records of the influence of the weather on agricultural production. For many years he was inspector-general of marine, and applied his scientific acquirements to the improvement of naval construction. He died at Paris on the 13th of August 1782.